In my ‘Does it work?’ page on this blog, I explained that I hadn’t had my blood tested, so couldn’t comment on the way that a fasting diet would affect my cholesterol levels. Recently I changed doctors and the new one sent me for blood tests. Yesterday he discussed the result with me and told me that my cholesterol levels were too high and that I should be thinking about my food choices and my exercise levels.

I felt, well, incredulous. I am now at the lower end of the ideal weight range for my height and build, my blood pressure is where it should be, I’m eating more healthily than ever, I don’t touch junk food, my exercise levels are above average and I have to sit and listen to a lecture about my lifestyle choices? Armed with my ‘too high’ numbers, I came home seething and spent an hour or two on the Internet, trying to work out what the numbers I’d been given really meant.

On the face of it, the high total cholesterol doesn’t look good. And what about all that ‘bad cholesterol’?!

Except… when I started reading about LDL, it became clear that calling it ‘bad’ is misleading, because there are two different types of LDL. The bad type is the small dense variety which infiltrates the walls of blood vessels and deposits gunk in them. The other type is larger and often described as ‘fluffy’: it doesn’t cause the same damage to the blood vessels.

So how do you know which type you have? There are tests which can tell you, but a simple way of determining the type of LDL in your blood is to look at the measurements of HDL and triglycerides. If your HDL number is low and your triglycerides one high, then your LDL is likely to be the dangerous, small dense type. If HDL is high and triglycerides low (as mine are), then your LDL is likely to be the benign kind. And high levels of HDL actually have a protective effect. Turns out, it’s the HDL and triglyceride numbers that are the best predictor of cardiovascular disease – not the LDL one.

Having done this research, I’m now happy with my numbers. What bothers me is that my doctor doesn’t seem to understand them and that I had to listen to his standard lecture on healthy eating. Not impressed…